A rotary joint is known, for example, from DE 102007057780 and essentially comprises a bearing inner ring that is surrounded coaxially by a bearing outer ring. Between the bearing inner ring and bearing outer ring there are rolling bodies.
If the mutual rotation between the bearing inner ring and bearing outer ring is to be limited to a specified rotational angle, it is typical to provide a so-called path limiting device. In general, this path limiting device is realized by a round raceway provided approximately on the outer lateral surface of the bearing inner ring. This raceway is engaged by one or two stops. A tab formed, in this case, on the inner lateral surface of the bearing outer ring projects into this raceway. If the raceway is provided with two stops, the free rotation of the bearing inner ring and bearing outer ring is limited, because the tab engages in the annular space between two stops and can be moved only between these stops. As can be easily seen, the mutual distance of the two stops can very easily set the desired rotational angle. If a mutual rotation of nearly 360° is to be realized, it is sufficient to provide only one stop. In this case, the rotational angle is defined largely by the width of one stop in the circumferential direction.
It is also known to provide rotary joints with brakes that provide for an instantaneous blocking of the rotation of the bearing outer ring relative to the bearing inner ring. In the cited publication, this is realized so that a brake disk is provided on one end side of the bearing outer ring and this brake disk interacts with a brake pad that is formed on the end side of the bearing inner ring, wherein this brake pad points in the same direction as the end side of the bearing inner ring and can be moved by an electromagnet in the direction of the rotational axis against the brake disk or away from this brake disk.
However, for rotary joints with path limiting devices it has been found to be disadvantageous that the stops can only realize rotational angles of less than 360°. This means a considerable limitation in use. For example, if the tab contacts the stop, which should correspond, for this view, to a rotational angle of 360°, further turning cannot realize a desired rotational angle, for example, of 400°,due to the effect of the stop. Instead, for realizing the desired rotational angle of 400° starting from the 360° position, it must be turned back over a large rotational angle of 320°.